sturtevant



(No Model.) 7

T. L. STURTEVANT.

ATTRITION MILL.

a. ma

UNITED STATE-s ATENT Fries.

THOMAS L. STURTEVANT, OF FRAMINGHAM, ASSIGNOR OF PART OF HIS RIGHT TO CHARLOTTE J. BOWKER, OF BOSTON, MASSACHUSETTS, AND E. LEWIS STURTEVANT, OF GENEVA, NEW YORK.

ATTRlTlON-MILL.

SPECIFICATION forming part of Letters Patent No. 269,481, dated December 19, 1882.

Application filed April 26, 1882.

(No model.)

To all whom it may concern:

Be it known that I, THOMAS LEGGETT STURTEVANT, a citizen; of the United States, residing at Framingham, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements -in Attrition-Mills; andIdo hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to a class of attritionmills for grinding phosphates, ores, grain, and other materials of. a class in which the material to be ground furnishes its own self-renew ing grinding-surlaces-in other words, in which the operation of'grinding is effected simply by attrition between the particles of the material.

'A notable instance of the class of mills to which my present improvements especial] relate is shown and described in Letters Patent of the United Statesiissued to myself on the 28th day of March, 1882, in which a portion of the unground material is kept bodily in rotary motion by a recessed rotary head, while the remainder of the unground material remains comparatively stationary Within asuitable case surrounding or immediately connected with such rotary head.

The objects of these improvements, are, first, to enable the circular edge most exposed I V to wear of the rotary head to be renewed as wear ensues, which I accomplish by the employment of a false or movable lining to such head, confined in place by bolts or other means which enable it to be adjusted in position within the head as occasion requires.

A second object of my improvements is to provide means for effectually and rapidly removing the flour or powder as fast as it forms, thereby facilitating the grinding operation by preventing clogging of the unground portions of the material. this feature in my improvements being effected by the employment, in combination with the rotary head, of a case or receiver for containing, in connection with suitable side housings, the bulk of the material to be ground, which case revolves uponits supports, and isformed with cells or depressions into which the powdered material falls, and by which such flour is raised to a point above the mass of unground material and allowed to drop, and is then removed by a suction-fan or other means, the rotary receiver or case constituting a continuous elevator to receive and raise the powder from 63 the unground material to a point whereit may be readily removed.

The drawings accompanying this specification represent, in Figure 1, a side elevation, in Fig. 2 a vertical and longitudinal section, 6 and in Fig. 3 a cross-section, of an attritionmill containing my improvements. Fig. 4 is a modification ofthe elevator to be explained.

In these drawings, A represents a circular head or disk, recessed or chambered in front, and at rear secured to one end of a horizontal rotary shaft, B, mounted in suitable standards, G U, and provided with pulleys A B, the latter being the driver. One edge of the head A revolves in close proximity to the rear 7 side of an upright tlat standard or housing,

a, erected upon the floor of the apartment, near standard (3, this standard or housing a having a twin standard, a, erected parallel to iton the side away from standard 0, the intermediate space being occupied by the rotary receiver hereinbet'ore referred to. A circular opening, I), is created in the standard at opposite the head A, this opening being of equal diameter with the outer circumference of such head. To provide means for compensating for wear about the edge of the head A, which is within opening b, or about the outer margin of the opening b, I employ an adjustable lining, c, which is a tube closely filling the bore or chamber of such head, this lining being socured in place within the head by bolts 0, as shown in the drawings, or by other means which will enable such lining to be adjusted 5 in position and fed outward as occasion requires. The outer end of the lining 0 protrudes beyond the margin of the bore of the horizontal shaft, g,

head and extends into and closely fills the aperture 1) in the housing a. In the operation of mills of this construction about the only wear ensuing upon the parts is at the inner margin or mouth of the chamber in the rotary head, or, in the present instance, the margin of the opening I), which is in contact to a greater or less extent with some portions of the unground material in the receiver. The lining enables the worn surface to be renewed as occasion requires, and in practice I prefer to construct such lining of chilled cast-iron or other very hard material, to resist efiects of abrasion as long as possible.

D in the accompanying drawings represents a circular ring composed of a flat band, such ring being situated uprightly between the housings a a, and maintained in position thereat by horizontal anti-friction rollsd d, 810., pivoted between such housings and distributed about and bearing upon the circumference of the ring-plate D and constituting bearin gs to permit the latter to rotate. The ring-plate D is put in rotary motion (preferably in a direction opposite to that of the head A) by an annular toothed rack, e,formed upon its circumference, which rack engages with and is driven by a pinion, f, secured to the outer end of a mounted in hearings in the lower part of the standard 0, this shaft 9 being put in motion by a belt, gear, or toothed wheel from the pulley A or by gearing or other mechanical means.

Within the inner periphery of the ring-plate D, I create by any suitable means a series of cells, depressions, or inelosures, t t, 850., as shown in Figs. 2 and 3 of the drawings, and at the upper part of each housing a a, I provide openingsj or k, as shown in said figures. The opening j is the filling-mouth of the mill, through which the unground material is supplied, while the opening provides an outlet for the powderraised by the ring-plate D, this outlet It being connected with a suction-fan or other means for removing such powder.

In the use of this mill the material to be ground is supplied to the interior of the ringplate D, or, more strictly speaking, to the receiver bounded by such plate on one hand and the housings acton the other, as fast as is requisite to supply the demand. A portion of the material to be ground fills the chamber of the head Aand rotates with it to provide the requisite moving grinding-surface, while the remainder in the receiver, under the action of the rotary ring-plate, tumbles about to a greater or less extent, the result being that between the two forces the materials are continually being reduced to powder. A certain proportion of the lightest portion of the powder will bedrawn directly upward through the receiver and discharged by way of the outlet 70 without assistance from the rotary ring'plate D; but certain portions of this powder will tend to settle to the lower part and bottom of the receiver and clog the unground particles of the material. The pockets or cells,.arranged, as

driven by a suitable shaft,

before stated, inor on the inner face of ringplate D, receive this portion of the powder and constantly operate to elevate and discharge such powder through outlet 70, whence it is con-' veyed from the mill, the bulk of unground material generally throughout the receiver being disturbed or stirred by the rotations of the elevator and the separation of the flour thereby facilitated.

In lieu of elevating the powdered material by means of the pockets in the rotary ringplate, as explained, alternative means of effecting the same result would be to dispense with these cells as forming part of or secured to such ring-plate, and employ an endless band, E, supported upon suitable rollers and traveling about the lower part of said ringplate, (see Fig. 4,) this endless band carrying a series of buckets, F F, 850., equidistant from each other, and adapted to enter in succession peripheral openings G, &c., in the ring-plate, and receive and elevate the powder deposited in them as they travel in and out of these openings. In this case it would be well to employ a screen situated position as to receive the powder deposited upon it by the traveling buckets, the screen being so constructed and situated with respect to the filling-orifice j of the receiver as to return to such receiver the coarse particles in the powder, while the fine portion of such powder pass through the screen into asuitable receptacle.

In addition to or in lieu of the rotary ringplateD for agitating or tumbling the unground material in the receiver, a rotary agitator composed of a shaft contained centrally within the receiver and provided with radial arms may be employed, the shaft being rotated by a pulley and belt or otherwise. An agitator or stirrer of any suitable construction may be employed to efi'ect more general disturbance of the unground material than would be the case with the rotary ring-plate.

I claim- I 1. 1n a*trition-mills of the class before mentioned, the combination, with the rotary head carrying the moving portion of the unground material and the receiver containing the comparatively-stationary unground portion thereof, of a movable part to such receiver for removing, the ground portions of the material, substantially as set forth.

2. The combination, with the rotary head and housings, of the rotary receiver provided upon its inner periphery with cells to receive the ground portions of the material, substantially as described.

3. The combination, with the receiver, rotary head, and the adjacent housing or wall of the receiver, of the adjustable tubular lining closely fitting the bore of the rotary head and the opening in the housing opposite such head, substantially as explained.

4. The rotary recessed head supported and in combination with said shaft and the receiver composed of above the elevator in such 7. The combination of the receiver D with head A, having removable bushing c, whereby the edge of the head nearest said receiver may be removed and replaced as fast as worn.

In testimony whereof I afiix my signature in 15 presence of two witnesses.

THOS. LEGGETT STUR'IEVANT. Witnesses H. E. LODGE, F. G. SIMPSON. 

